SIMULATION OF THE SHADING PATTERN OF PERIODICALLY PRUNED TREES IN AGROFORESTRY SYSTEMS

One of the main difficulties in the development of agroforestry system s research is the size and high cost of experiments which cover an ade quate range of arrangements of trees and crops. One solution to this p roblem is to use simulation models to explore a wide range of designs and test only the best in the field. The present article presents a si mulation model for the shading pattern of periodically pruned trees. T he model permits to estimate the photosynthetic photon exposure during a user defined time in a field with trees once the location and dimen sions of the trees, the crop height, geographical latitude and atmosph eric transmittance are known. The field is divided into 50 x 50 cm squ ares and simulation is realized independently for all of them. The mod el includes the canopy transmittance parameters only for Erythrina poe ppigiana (Walpers) O.F. Cook, but modifying these parameters the model could be applied for any agroforestry tree species managed with perio dic prunings. The main application of the model is to explore theoreti cally the effect of the trees on the radiation regime above the crop i n agroforestry systems.